Incorporating ontology-based semantics into conceptual modelling

With the increasing complexity of applications and user needs, recent research has shifted from a data-information level to a human semantic level interaction. Research has begun to address the increasing use and development of ontologies in various applications, strongly motivated by the semantic web initiative. However, existing conceptual models are not rich enough to incorporate ontologies in one single conceptual schema. To improve this situation, it is necessary to refine modelling formalisms and make them more expressive while ensuring they remain semantically sound. We argue that conceptual modelling methodologies would be semantically richer if they were able to express the semantics of a domain that arises in concrete application scenarios. This paper investigates the incorporation of ontologies into three popular conceptual modelling methodologies, presenting the Ontological Entity-Relationship (OntoER) model, Ontological Object Role Modelling (OntoORM) and the Ontological Unified Modelling Language (OntoUML) class diagram. An extended conceptual framework for modelling ontologies and a transformation algorithm for mapping ontological constructs to relational schemata are provided so that querying the database through the conceptualisation of the database can be managed.     

A conceptual model for the logical design of temporal databases

Although widely advocated as a tool for the conceptual modelling of data, the Entity-Relationship (E-R) model [4] and its extensions are generally lacking in constructs to model the dynamic nature of the real world, making them inadequate for designing temporal databases. This research first extends the E-R model to a Temporal Event-Entity-Relationship Model (TEERM), by introducing events as an additional construct. Second, a method is proposed for mapping this conceptual model into a temporal relational model for the logical design of temporal relational databases with a corresponding set of integrity constraints. The model is illustrated with an example and evaluated using a set of criteria proposed by ^{Batini et al. [2]}. The model appears to be expressive, simple and easy to use, and should, therefore, aid the temporal database design process significantly.     

Accommodating mesodata into conceptual modelling methodologies

Mesodata modelling is a recently developed approach for enhancing a data model’s capabilities by providing for more advanced semantics to be associated with the domain of an attribute. Mesodata supplies both an inter-value structure to the domain and a set of operations applicable to that structure that may be used to facilitate additional functionality in a database. We argue that conceptual modelling methodologies would be semantically richer if they were able to express the semantics of complex data types for attribute domains. This paper investigates the accommodation of mesodata into the entity-relationship and object role modelling, presenting the Mesodata Entity-Relationship (MDER) model and Mesodata Object Role Modelling (MDORM), which show how the mesodata concept can be incorporated into conceptual modelling methodologies to include the semantics of complex-domain structures.     

Axiomatizing functional dependencies in the Higher-Order Entity-Relationship Model

A finite axiomatization of functional dependencies on conceptual database schemata is presented which naturally generalizes the well-known Armstrong axioms. The underlying conceptual data model is the Higher-Order Entity-Relationship Model.     

Design of statistical databases: A methodology for the conceptual step

The aim of the conceptual step in database design is to describe data involving in the application in a formal and abstract way, without any concern to the specific model and language chosen for the implementation. In statistical applications, data are described at different levels of aggregation, from elementary facts of the reality to complex aggregations such as classifications, time series, indexes. The paper describes a methodology for conceptual design of statistical databases that provides the designer suitable strategies for defining such different levels of aggregation starting from user requirements, and checking the completeness, coherence and minimality of the conceptual schema at the different levels. The methodology makes use of two data models for the representation of data: for elementary data the Entity-Relationship model, widely used in database applications, and for summary data a new model is proposed, designed to be an effective trade-off between expressive power and simplicity of use.     

Multiple views and abstractions with an extended-entity-relationship model

The features of the Entity-Relationship model are examined, as a means for representing both the conceptual schema and the external schema in a database system. In order to serve in this dual capacity, its modelling features are extended to support multiple user views. We show how to represent a model and present a suitable diagrammatic technique. To represent these concepts at the user level we propose a data definition language with a concise and simple structure. Furthermore, guidelines are given for interfacing the E-E-R schema with existing DBTG-like systems.     

An approach to developing complex database schemas using form types

In this paper we consider an approach to developing complex database schemas. Apart from the theoretical model of the approach, we also developed a CASE tool named Integrated Information Systems*Case, R.6.2 (IIS*Case) that supports the practical application of the approach. In this paper the basis of our approach to the design and integration of database schemas and ways of using IIS*Case is outlined. The main features of a new version of IIS*Case, developed in Java, are described. IIS*Case is based on the concept of ‘form type’ and supports the conceptual modelling of a database schema, generating subschemas and integrating them into a relational database schema in 3NF. IIS*Case provides an intelligent support for complex and highly formalized design and programming tasks. Having an advanced knowledge of information systems and database design is not a compulsory prerequisite for using IIS*Case. IIS*Case is based on a methodology of gradual integration of independently designed subschemas into a database schema. The process of independent subschema design may lead to collisions in expressing real‐world constraints. IIS*Case uses specialized algorithms for checking the consistency of constraints embedded in a database schema and its subschemas. This paper briefly outlines the application of the process of detecting collisions, and actions the designer may take to resolve them. Copyright © 2007 John Wiley & Sons, Ltd.     

Foundations of entity-relationship modeling

Database design methodologies should facilitate database modeling, effectively support database processing, and transform a conceptual schema of the database to a high-performance database schema in the model of the corresponding DBMS. The Entity-Relationship Model is extended to theHigher-orderEntity-RelationshipModel (HERM) which can be used as a high-level, simple and comprehensive database design model for the complete database information on the structure, operations, static and dynamic semantics. The model has the expressive power of semantic models and possesses the simplicity of the entity-relationship model. The paper shows that the model has a well-founded semantics. Several semantical constraints are considered for this model.     

Conceptual Data Modeling for Spatiotemporal Applications

Many exciting potential application areas for database technology manage time-varying, spatial information. In contrast, existing database techniques, languages, and associated tools provide little built-in support for the management of such information. The focus of this paper is on enhancing existing conceptual data models with new constructs, improving their ability to conveniently model spatiotemporal aspects of information. The goal is to speed up the data modeling process and to make diagrams easier to comprehend and maintain. Based on explicitly formulated ontological foundations, the paper presents a small set of new, generic modeling constructs that may be introduced into different conceptual data models. The ER model is used as the concrete context for presenting the constructs. The semantics of the resulting spatiotemporal ER model, STER, is given in terms of the underlying ER model. STER is accompanied by a textual counterpart, and a CASE tool based on STER is currently being implemented, using the textual counterpart as its internal representation.     

A survey of database design transformations based on the Entity-Relationship model

At present, the Entity-Relationship (ER) model is the most important paradigm for conceptual database design. Since the model was introduced in the mid-seventies, a large body of literature has been published on transforming conceptual ER schemas or diagrams into logical data models. The purpose of this paper is to survey this literature. A first focus is on transformation approaches from the ER model to traditional data models, i.e. to the relational, the network, or the hierarchical model; this is then complemented by a discussion of more recent transformations to object-oriented models. A second focus is on considering the process of reverse engineering, i.e. transformations from a logical model back into the ER model; finally, an overview of direct transformations between various logical data models is presented.     

数据库逆向工程方法比较与分析

从物理数据库恢复概念数据模型的过程称为数据库逆向工程(DBRE)。本文首先介绍了ER模型的主要构造子,然后描述了数据库逆向工程的概念和处理过程。接着分析了前期研究人员提出的多种逆向工程方法和主要CASE工具逆向工程方法的特点。     

基于UML的仓库管理数据库系统设计

本文主要针对基于UML的仓库管理数据库系统分析方法进行研究.在基于面向对象UML的平台上,以仓库管理为研究对象,对其需求模型和总体设计模型进行了分析设计,并结合基于UML建模语言的CASE工具Power Designer进行进一步的辅助分析,最终实现了数据库系统的设计.     

一种基于模型转换的数据仓库设计技术

该文比较了数据仓库数据库与传统操作型数据库,回顾了“规范的”操作型系统设计,介绍了三种典型的数据模型———实体关系模型、对象模型和维模型(星形模型)。提出了一种基于模型和模型转换的数据仓库设计工程方法。     

Subtyping and polymorphism in object-role modelling

Although Entity-Relationship (ER) modelling techniques are commonly used for information modelling, Object-Role Modelling (ORM) techniques are becoming increasingly popular, partly because they include detailed design procedures providing guidelines for the modeller. As with the ER approach, a number of different ORM techniques exist. In this paper, we propose an integration of two theoretically well founded ORM techniques: FORM and PSM. Our main focus is on a common terminological framework, and on the notion of subtyping. Subtyping has long been an important feature of semantic approaches to conceptual schema design. It is also the concept in which FORM and PSM differ the most in their formalization. The subtyping issue is discussed from three different viewpoints covering syntactical, identification, and population issues. Finally, a wider comparison of approaches to subtyping is made, which encompasses other ER-based and ORM-based information modelling techniques, and highlights how formal subtype definitions facilitate a comprehensive specification of subtype constraints.     

An integrated modelling framework to support manufacturing system diagnosis for continuous improvement

This paper proposes an integrated modelling framework for the analysis of manufacturing systems that can increase the capacity of modelling tools for rapidly creating a structured database with multiple detail levels and thus obtain key performance indicators (KPIs) that highlight possible areas for improvement. The method combines five important concepts: hierarchical structure, quantitative/qualitative analysis, data modelling, manufacturing database and performance indicators. It enables methods to build a full information model of the manufacturing system, from the shopfloor functional structure to the basic production activities (operations, transport, inspection, etc.). The proposed method is based on a modified IDEF model that stores all kind of quantitative and qualitative information. A computer-based support tool has been developed to connect with the IDEF model, creating automatically a relational database through a set of algorithms. This manufacturing datawarehouse is oriented towards obtaining a rapid global vision of the system through multiple indicators. The developed tool has been provided with different scorecard panels to make use of KPIs to decide the best actions for continuous improvement. To demonstrate and validate both the proposed method and the developed tools, a case study has been carried out for a complex manufacturing system.     

Building a database feedback system

Previous research has shown that user accuracy in database retrievals can be greatly improved by the provision of a conceptual level interface. However, there are still certain queries that are quite difficult. This calls for a feedback system which can provide feedback, regarding the system's interpretation of the query, to further enhance the user's accuracy, with the ultimate goal of 100% accuracy. This paper describes the design and implementation of a database feedback system on top of MERM, a Modified Entity-Relationship Model based DBMS. Specifically, the database feedback system performs the following functions:—it provides English translation of the query;—it shows syntax errors and suggests possible solutions to rephrase a syntactically wrong query; and—it shows likely semantic errors and suggests possible solutions.The results of a laboratory experiment which studies the effects of the database feedback system on user's performance is also reported in this paper.     

Reconciling requirement-driven data warehouses with data sources via multidimensional normal forms

Successful data warehouse (DW) design needs to be based upon a requirement analysis phase in order to adequately represent the information needs of DW users. Moreover, since the DW integrates the information provided by data sources, it is also crucial to take these sources into account throughout the development process to obtain a consistent reconciliation of data sources and information needs. In this paper, we start by summarizing our approach to specify user requirements for data warehouses and to obtain a conceptual multidimensional model capturing these requirements. Then, we make use of the multidimensional normal forms to define a set of Query/View/Transformation (QVT) relations to assure that the conceptual multidimensional model obtained from user requirements agrees with the available data sources that will populate the DW. Thus, we propose a hybrid approach to develop DWs, i.e., we firstly obtain the conceptual multidimensional model of the DW from user requirements and then we verify and enforce its correctness against data sources by using a set of QVT relations based on multidimensional normal forms. Finally, we provide some snapshots of the CASE tool we have used to implement our QVT relations.     

Reconciling requirement-driven data warehouses with data sources via multidimensional normal forms

Successful data warehouse (DW) design needs to be based upon a requirement analysis phase in order to adequately represent the information needs of DW users. Moreover, since the DW integrates the information provided by data sources, it is also crucial to take these sources into account throughout the development process to obtain a consistent reconciliation of data sources and information needs. In this paper, we start by summarizing our approach to specify user requirements for data warehouses and to obtain a conceptual multidimensional model capturing these requirements. Then, we make use of the multidimensional normal forms to define a set of Query/View/Transformation (QVT) relations to assure that the conceptual multidimensional model obtained from user requirements agrees with the available data sources that will populate the DW. Thus, we propose a hybrid approach to develop DWs, i.e., we firstly obtain the conceptual multidimensional model of the DW from user requirements and then we verify and enforce its correctness against data sources by using a set of QVT relations based on multidimensional normal forms. Finally, we provide some snapshots of the CASE tool we have used to implement our QVT relations.     

Meta-CASE: Is the game worth the candle?

The current generation of CASE (Computer Aided Software Engineering) tools is too inflexible to provide adequate modelling support. One of the proposed solutions to this problem is the development of so-called CASE shells. A CASE shell is a method independent CASE tool, which may be instantiated with a specific method to become a CASE tool supporting that method. As such, a CASE shell provides complete flexibility. This paper does not address the benefits of CASE shells, as they are completely clear, but focuses on the feasibility of this concept from a theoretical as well as a practical point of view.     

The category concept: An extension to the entity-relationship model

An enhanced version of the Entity-Relationship (ER) data model called the Entity-Category-Relationship (ECR) data model is presented. The principal extension is the introduction of the concept of a category. Categories permit the grouping of entities from different entity types according to the roles they play in a relationship, as well as the representation of ISA and generalization hierarchies. The structures of the ECR data model are defined, and a graphic representation technique for their display is presented. Language operations to define and use an ECR database are defined. Two realistic examples of the use of the ECR model for database design are demonstrated. The examples show how ECR structures can be directly mapped into relational and network structures. The definition of derived relationships on an ECR database gives the power to phrase higher order recursive queries in a first order query language.